Suspended Exploratory Well Costs - Aging by Geographic Area and the Year the Costs Were Suspended (Detail) (USD $) In Millions, unless otherwise specified						12 Months Ended
	Dec. 31, 2013 Project		Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 Aging of Capitalized Exploratory Well Costs, Period One [Member]	Dec. 31, 2013 Aging of Capitalized Exploratory Well Costs, Period Two [Member]	Dec. 31, 2013 Aging of Capitalized Exploratory Well Costs, Period Three [Member]	Dec. 31, 2013 United States Onshore [Member]		Dec. 31, 2013 United States Onshore [Member] Aging of Capitalized Exploratory Well Costs, Period One [Member]	Dec. 31, 2013 United States Onshore [Member] Aging of Capitalized Exploratory Well Costs, Period Two [Member]	Dec. 31, 2013 United States Onshore [Member] Aging of Capitalized Exploratory Well Costs, Period Three [Member]	Dec. 31, 2013 United States Offshore [Member]		Dec. 31, 2013 United States Offshore [Member] Aging of Capitalized Exploratory Well Costs, Period One [Member]	Dec. 31, 2013 United States Offshore [Member] Aging of Capitalized Exploratory Well Costs, Period Two [Member]	Dec. 31, 2013 United States Offshore [Member] Aging of Capitalized Exploratory Well Costs, Period Three [Member]	Dec. 31, 2013 International [Member]		Dec. 31, 2013 International [Member] Aging of Capitalized Exploratory Well Costs, Period One [Member]	Dec. 31, 2013 International [Member] Aging of Capitalized Exploratory Well Costs, Period Two [Member]	Dec. 31, 2013 International [Member] Aging of Capitalized Exploratory Well Costs, Period Three [Member]
Capitalized Exploratory Well Costs [Line Items]
Suspended exploratory well costs	$ 2,232		$ 2,062	$ 1,353	$ 935				$ 160					$ 461					$ 1,611
Suspended exploratory well costs capitalized for a period less than one year after completion of drilling	711	[1]							143	[1]				126	[1]				442	[1]
Suspended exploratory well costs capitalized for a period greater than one year after completion of drilling						$ 669	$ 328	$ 524			$ 6	$ 1	$ 10			$ 137	$ 24	$ 174			$ 526	$ 303	$ 340
Aging of Capitalized Exploratory Well Costs, Period Start Date						Jan. 01, 2012	Jan. 01, 2011
Aging of Capitalized Exploratory Well Costs, Period End Date						Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Projects with exploratory well costs capitalized for a period greater than one year after completion of drilling	14

[1] Excludes additions subsequently reclassified to proved properties within the same year.